A silver halide photographic material is required to be high sensitive and produce less fluctuation in the photographic properties during storage after production and after photographing until development processing.
Of the fluctuation of the photographic properties after photographing until development processing, with respect to the prevention of latensification, a method of using a hardening agent having an active vinyl group in combination with a triazine based compound is disclosed in JP-A-59-162546 (the term "JP-A" as used herein means a "published unexamined Japanese patent application").
However, the above method is not sufficient in the preventing effect and a further improvement has been desired.
On the other hand, in a full color photographic materials a multilayer structure comprising a plurality of emulsions having different spectral sensitivities is used to achieve the object of a full color photograph. However, although the emulsions for such a usage have been considerably improved, fog, intensification and fading of a latent image are liable to occur, therefore, they are not necessarily sufficient. 2-Hydroxyamino-1,3,5-triazines, for example, are useful for the improvement of such storage stabilities. However, the storage stability of each layer varies according to the emulsion used in each layer. Therefore, a method to improve the storage stability of the latent image of the emulsion of a specific layer has been strongly desired in recent years.
Many of known 2-hydroxylamine-1,3,5-triazines are diffusible, therefore, they have a drawback such that their effects are exerted to emulsions of layers other than the objective layer. On the other hand, hydroxamic acids having a specific structure are disclosed in U.S. Pat. No. 4,339,515, 4,330,606, JP-A-59-198453 and JP-A-3-293666, but the use purposes of them are different from the object of the present invention and, further, their effects of the improvement of the storage stability of a latent image and the functions to the emulsion of solely a specific layer are not sufficient. Accordingly, the development of a method to largely improve the storage stability of the latent image of only the objective layer has been strongly desired.
The present invention is to provide a method to improve the above described storage stability of the emulsion and the stability of the latent image of a specific layer.
The present inventors have eagerly studied the method of improving the storage stability of the emulsion produced and the storage stability of the latent image to solve the above problems. As a result of various investigation particularly about the carbon atom number and the kinds of the substituents, a completely novel N-alkylhydroxamic acid based compound of the present invention has been discovered.
Further, it has been found that the compound of the present invention can achieve the objects of the present invention, when added to a silver halide photographic material, without changing the hue of the color formed, affecting the dye-forming speed of the coupler, accelerating the decomposition of the coupler and the color formed, deteriorating the film strength, or fogging the emulsion.
Moreover, of the compounds for use in the present invention, the compound represented by formula (III) is a completely novel compound which has not been known in the past. The photographic usefulness of this compound has become clear solely by the investigation of the present inventors.